G: Water column picoplankton Objectives
2.5 Biodiversity, evolution and genetics
2.5.3 Biogeography, speciation and biodiversity of Antarctic Asellota (M. Raupach)
Objectives
The Isopoda and especially the Asellota are one of the most numerous and important elements of the benthos in all oceans. They are the dominating taxon among crustaceans in the deep sea. Little is known about Antarctic Asellota, and no molecular data are available. Numerous deep-sea Asellota were collected during the ANDEEP expeditions (2002, ANT XIX/3+4) and preserved for molecular studies. Preliminary results of ssu rDNA-gene analyses indicate a multiple colonization of the Antarctic deep sea. This ecosystem has to be considered as a special case. It was colonized not only by Asellota from the neighbouring deep-sea basins but also by shelf forms.
The relatives of some blind deep-sea forms, e.g. the Acanthaspidiidae, possess eyes and are endemic to the Antarctic shelf. Hence some deep sea species may have evolved from immigrating shelf forms, a phenomenon called "polar submergence". Interestingly, a great number of typical deep-sea species can also be found on the Antarctic continental shelf ("polar emergence"). Submergence events can be found within other isopod suborders, too: first studies on serolid isopods (Sphaeromatidea) indicate several independent invasions of the deep sea. Since both emergence and submergence can be observed in Antarctica, the evolution of the shelf fauna is closely related to the adjacent deep sea. With additional asellote species from the sheif we will be able to reconstruct the phylogeny of the Asellota and the colonization of the Antarctic deep sea in more detail.
Tab. 17 DNA extractions frorn Asellota
Su border Farnily Number of DNA Extractions
Asellota Acanthaspidiidae 33
Desmosomatidae 12
Haploniscidae 1
Janiridae sensu Wolff 11
Joeropsididae 4
Macrostylidae 1
Munnopsididae 3 2
Munnidae 15
Pararnunnidae 9
Stenetriidae 6
Valvifera Idoteidae 6
Cyrnothoidea Gnathiidae 4
Work at sea
In total, 1563 isopods were collected. 210 specimens were sampled around Bouvet island while 1353 animals were collected in the high Antarctic. At least 69 species were found, 47 of them belonging to the Asellota. In addition, 11 different species of the Asellota were identified.
Owing to their small size (1-10 mm), most Asellota were found in the epibenthic sledge samples. The whole sample was placed in ethanol 96%
as quickly as possible after sampling to avoid DNA degradation by enzymatic activity. The DNA of 124 asellote specimens from 10 different families and 10 animals from other isopod suborders (Table 17) was extracted and purified from several separated legs of the specimens, using the QIAmp Tissue Kit (Qiagen GmbH, Hilden), following the extraction protocol. The amputated animals were preserved in ethanol 96% for future morphological and molecular studies. Further processing (PCR, DNA sequencing, phylogenetic analysis) will be carried out in the laboratory of the Ruhr-Universitä Bochum.
Fast evolving genes like the 16s rRNA gene or cytochrome oxidase 111 gene are quite useful for population genetics, while slow evolving genes, for example the complete 18s rRNA, will be used to investigate older phylogenetic events within the Asellota.
Preliminary results - Isopoda of Bouvet Island
The position of Bouvet Island makes this region very interesting for phylogenetic and biogeographic studies, but currently only a small amount of erratic data exists. The Isopoda around Bouvet Island are poorly understood, and no molecular data are available. During this expedition 21 0 isopods were collected with four Agassiz trawls at different depths ranging from 122 to 553 metres (Table 18). Within the Valvifera only one antarcturid species (49 animals) was found but in all samples. 60 specimens of the only found serolid species were obtained from depths between 247 and 553 metres.
Isopoda belonging to the Cymothoidea were found at all depths, Gnathia sp.
(5) at the two most shallow stations while Aega sp. (11) was sampled at the two deeper stations. In addition to these taxa at least 10 different species of the Asellota (85 animals) were collected, mainly from the shallow samples.
Many of these species may be unknown.
Tab. 18 Isopoda of Bouvet Island
Valvifera Antarcturidae x x x X
Sphaeromatidea Serolidae x x X
Cymothoidea Aegidae Aega sp. X X
Gnathiidae Gnathia sp. X X
Asellota Acanthaspidiidae lanthopsis ruseri X
Janiridae s. Wolff X
Joeropsididae Joeropsis sp. 1 X
Munnopsididae Echinozone quadrispinosa X X X
Coperonus sp. 1 x x x
Munnidae Munna sp. 1 X X
Munna sp. 2 X
Munna sp. 3 X
Pararnunnidae X
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High Antarctic Isopoda1353 specimens of five isopod suborders were collected in the high Antarctic.
They belong to the suborders Cymothoidea (232 specimens), Valvifera (1 1 I ) , Anthuridea (39), Sphaeromatidea (40) and Asellota (931). The Valvifera animals of the families Antarcturidae and ldoteidae were very abundant (69 = 62%). Specimens of the species Accalafhura giganfissima (12 = 31%) dominated within the small number of Anthuridea while animals of the family Gnathiidae represented the most abundant taxon within the Cymothoidea (143 = 62%). Besides this one animal of the strange ectoparasitic isopod species Zonophryxus quinquedens was collected. Ceratoserolis frilobitoides with 28 specimens was the most abundant species of the Sphaeromatidea (70%).
Sphaeromatidea were surprisingly rare, as this taxon is thought to be a characteristic element of the Antarctic benthos. This group may be more abundant below our preferred sampling depth of 250 to 350 m. The most abundant taxon within the Isopoda were the Asellota, mostly collected with the epibenthic sledge (Table 19). They included 10 families with at least 47 species. The Munnopsididae, with 310 animals (23%), were the dominating family within the asellote isopods. Besides this 9 specimens of the Haploniscidae, a typical deep-sea family, were recorded from the Antarctic shelf for the first time.
Results 102
Tab. 19 Asellota collected with the epibenthic sledge.
Munnopsididae
Paramunnidae
Acanthaspidiidae Acanfhaspidia drygalskii X
lanthopsis ruseri X X
lanthopsis rnultispinosa X X
lanthopsis nasicornis X X
Desmosomatidae Species 1 (Desrnosomatinae) X X X
Species 2 (Desmosomatinae) X
Species 3 (Eugerdellatinae) X X
Species 4 (Desmosomatinae) X
Species 6 (Eugerdellatinae) X
Haploniscidae Haploniscus sp. X X
Janiridae sensu Woiff Species 2 X X
Species 3 X
Neojaera antarcfica x x x
Species 5 X
Species 6 x x x
Joeropsididae Joeropsis sp. 2 X X
Macrostylidae Macrostylis sp. X
Munnidae Munna sp. 6 X X
Echinomunna horrida X
Munna sp. 10 X
Munna globicaudata x x x
Munna spicata X
Coperonus sp. 2 x x x
Coperonus sp. 3 X X
Species 1 (Eurycopinae) X X
Species 2 (Eurycopinae) X
Species 3 (Eurycopinae) X
Species 1 (Syneurycopinae) X
Echinozone rnagnifica X
Echinozone quadrispinosa x x x X
Echinozone spinosa X X X
Sursurnura robustissirna X
Species 3 X
Species 4 X
Species 6 X
Species 7 X X
Species 8 X
Stenetriidae Stenetriurn sp. 2 X
Tenupedunculus acutum x x x
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Isopod species determined so far:Asellota:
Sursurnura robustissima (Monod, 1925); Echinozone quadrispinosa (Beddard, 1886); Echinozone spinosa Hodgson, 1902; Echinozone magnifica Vanhäffen 1914; Munna globicauda Vanhoffen, 1914; Munna spicata Teodorczyk & Wägele 1994; lanthopsis rnultispinosa Vanhoffen, 1914;
lanthopsis nasicornis Vanhoffen, 1914; lanthopsis ruseri Vanhoffen, 1914;
Acanthaspidia drygalskii Vanhoffen, 1914; lathrippa sarsi (Pfeffer, 1887);
Tenupedunculus acutum Vanhoffen, 1914; Echinomunna horrida Vanhoffen, 19 14; Neojaera antarctica (Pfeffer, 1887).
Sphaeromatidea:
Ceratoserolis trilobitoides (Eig hts, 1 833).
Valvifera:
Glyptonotus antarcticus Eights, 1853.
Cymothoidea:
Zonophryxus quinquedens Barnard, 1913; Natatolana albinota Vanhöffen 1914; Natatolana obtusata (Vanhöffen 1914); Gnathia antarctica (Studer, 1884).
Anthuridea:
Accalathura gigantissima Kussakin, 1967.
2.5.4 Biodiversity and genetics of Cnidaria and Porifera (J.M. Gili, E. Rodriguez, N. Teixido, B. Vendrell) A: Cnidarian biodiversity and reproduction
Objectives
As a continuation of previous studies within the EASIZ Programme and to contribute to the current knowledge of the Antarctic cnidarian fauna, our main objective was focused on species composition, density, and demographic features of cnidarian communities in the eastern Weddell Sea. Special attention was placed on the anthozoan fauna. Furthermore, reproductive and output features of various gorgonians and actiniarian species were investigated for temporal comparisons with previous EASIZ cruises carried out in summer and autumn.
Work at sea and preliminary results
Material was collected from 47 stations, mainly using Agassiz and Bottom trawls, but we also obtained some samples from Rauschert's small dredge and the epibenthic sledge. Hydrozoans and gelatinous plankton, mainly jellyfish and siphonophores, were fixed in buffered 10% formalin. For the anthozoan material, the most abundant group among the Cnidaria in this cruise, different methods were used. Octocorals were fixed in buffered 10%
formalin, while soft hexacorals (actiniarians and scleractinians) were maintained in the cool room and relaxed using menthol crystals. After relaxing, these specimens were fixed in buffered 10% formalin. Octocoral and scleractinian material will be transferred to 70% ethanol after the fixation period. Small portions of tissues were obtained from fresh specimens and directly fixed in 96% ethanol for further molecular studies. Other material was frozen for alloenzyme and secondary metabolite analyses.
Preliminary results
The hydrozoan material, as the gelatinous plankton collected, will be studied at the CMIMA-CSIC (Barcelona). Hydrozoans were present at all stations of the sampled areas except for those stations corresponding to Atka Bay, West of Kapp Norvegia and the Spiess Seamount. This absence may be due to the different sampling effort in those areas.
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Taxonomy and distribution of anthozoans in the eastern Weddell SeaPart of the collected anthozoan material was identified to species level on board while others (mainly actiniarians) remain to be identified. The detailed study of the anthozoan material will be carried out at the USE (Seville).
During this cruise we collected 61 species of Anthozoa. 27 species belong to the subclass Octocorallia, and 32 to the subclass Hexacorallia. Within the octocoral species there were 27 Alcyonacea (4 stolonate octocorals, 5 soft corals, 18 gorgonians) and 2 Pennatulacea. Within the hexacoral species the order Actiniaria was the most abundant with 28 species, followed by 3 Scleractinia, and one Zoantharia. A preliminary list of the number of anthozoan species per station, grouped by areas is shown in Table 20.
Compared to preliminary results obtained from the previous EASIZ II and 111 cruises, in which 63 and 93 anthozoan species were collected respectively, we observed a slight decrease in the number of species collected during the present cruise (61 anthozoan species). However, if we include only the eastern Weddell Sea area (Austisen, Drescher Inlet, and Kapp Norvegia), the number of collected anthozoan species is quite similar for the three cruises (both EASIZ cruises included stations in the Antarctic Peninsula region).
The Austisen area yielded the highest number of species, followed by northern Kapp Norvegia and Drescher Inlet (40, 37, and 21 anthozoan species, respectively). In the EASIZ II cruise the northern Kapp Norvegia area presented the highest number of species. The higher species richness at Austisen is probably due to the high number of stations sampled. The lower number of species found for Drescher Inlet may be related to the fact that the deepest stations (more than 500 m depth) were located in this area. We suggest that the highest anthozoan species number is found at stations between 200 and 400 m depth.
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Taxonomy and distribution of anthozoans at Bouvet and Spiess Seamount Most of the anthozoan species collected off Bouvet and Spiess Mountain still remain unidentified, The expected identification will clarify biogeographic and phylogenetic traits of anthozoan fauna from these areas in relation with the high Antarctic fauna. However, the new collected material will extend the distribution records for many species. Regarding the actiniarian material, eight species were collected from Bouvet Island (where four of them are currently cited) and two species from the Spiess Seamount (where none has been cited before) (Carlgren 1927, 1928; Fautin 2004).-
Reproduction of anthozoansColonies of six selected gorgonian species, Ainigmaptilon antarcticus, Dasysfenella acanfhina, Fannyella rossii, F. spinosa, and Thouarella sp. 2 were collected to compare the reproductive state during spring, summer, and autumn conditions. A detailed study of the quantitative reproductive features (size ranges of oocytes, presence of larvae ...) will be done at the CMIMA-CSIC (Barcelona) and at the USE (Seville).
Colonies of the gorgonians Dasystenella acanfhina, Thouarella sp. 2, Tokoprimno sp., and of the pennatulacean Umbellula sp. seemed to exhibit development of reproductive tissues. Within the actiniarian material three different reproductive strategies have been observed: larval spawning, internal brooding (within the family Actinostolidae) and external brooding (Epiactis cf.
Results 105 georgiana). Although the detailed histological study remains to be done, differences among juvenile sizes of the external brooder species Epiactis cf georgiana were observed between material collected in autumn and material collected in spring, during the present cruise (juvenile size ranges seem to be higher in autumn than in late spring).
Results 106
325 324 308 297 293 292 283 ..- 282 - - ~
233 ... 232
281 280 279 278 276 253 251 248 109 - ... 039
339 336 274 265 259 237 245 175 174 173 166 163 161 148 146 1 4 4 140 132 121 ... 090 .. .-- 048
029 028 020 01 9 St.
Results 108
B: Genetic studies in sponges